4 * R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
6 * SPDX-License-Identifier: GPL-2.0+
13 #include <asm/byteorder.h>
15 #include <linux/ctype.h>
17 #include <linux/math64.h>
20 static void uppercase(char *str
, int len
)
24 for (i
= 0; i
< len
; i
++) {
30 static int total_sector
;
31 static int disk_write(__u32 block
, __u32 nr_blocks
, void *buf
)
38 if (cur_part_info
.start
+ block
+ nr_blocks
>
39 cur_part_info
.start
+ total_sector
) {
40 printf("error: overflow occurs\n");
44 ret
= blk_dwrite(cur_dev
, cur_part_info
.start
+ block
, nr_blocks
, buf
);
45 if (nr_blocks
&& ret
== 0)
52 * Set short name in directory entry
54 static void set_name(dir_entry
*dirent
, const char *filename
)
56 char s_name
[VFAT_MAXLEN_BYTES
];
58 int period_location
, len
, i
, ext_num
;
63 len
= strlen(filename
);
67 strcpy(s_name
, filename
);
68 uppercase(s_name
, len
);
70 period
= strchr(s_name
, '.');
72 period_location
= len
;
75 period_location
= period
- s_name
;
76 ext_num
= len
- period_location
- 1;
79 /* Pad spaces when the length of file name is shorter than eight */
80 if (period_location
< 8) {
81 memcpy(dirent
->name
, s_name
, period_location
);
82 for (i
= period_location
; i
< 8; i
++)
83 dirent
->name
[i
] = ' ';
84 } else if (period_location
== 8) {
85 memcpy(dirent
->name
, s_name
, period_location
);
87 memcpy(dirent
->name
, s_name
, 6);
88 dirent
->name
[6] = '~';
89 dirent
->name
[7] = '1';
93 memcpy(dirent
->ext
, s_name
+ period_location
+ 1, ext_num
);
94 for (i
= ext_num
; i
< 3; i
++)
97 memcpy(dirent
->ext
, s_name
+ period_location
+ 1, 3);
99 debug("name : %s\n", dirent
->name
);
100 debug("ext : %s\n", dirent
->ext
);
103 static __u8 num_of_fats
;
105 * Write fat buffer into block device
107 static int flush_dirty_fat_buffer(fsdata
*mydata
)
109 int getsize
= FATBUFBLOCKS
;
110 __u32 fatlength
= mydata
->fatlength
;
111 __u8
*bufptr
= mydata
->fatbuf
;
112 __u32 startblock
= mydata
->fatbufnum
* FATBUFBLOCKS
;
114 debug("debug: evicting %d, dirty: %d\n", mydata
->fatbufnum
,
115 (int)mydata
->fat_dirty
);
117 if ((!mydata
->fat_dirty
) || (mydata
->fatbufnum
== -1))
120 startblock
+= mydata
->fat_sect
;
122 if (getsize
> fatlength
)
126 if (disk_write(startblock
, getsize
, bufptr
) < 0) {
127 debug("error: writing FAT blocks\n");
131 if (num_of_fats
== 2) {
132 /* Update corresponding second FAT blocks */
133 startblock
+= mydata
->fatlength
;
134 if (disk_write(startblock
, getsize
, bufptr
) < 0) {
135 debug("error: writing second FAT blocks\n");
139 mydata
->fat_dirty
= 0;
145 * Get the entry at index 'entry' in a FAT (12/16/32) table.
146 * On failure 0x00 is returned.
147 * When bufnum is changed, write back the previous fatbuf to the disk.
149 static __u32
get_fatent_value(fsdata
*mydata
, __u32 entry
)
156 if (CHECK_CLUST(entry
, mydata
->fatsize
)) {
157 printf("Error: Invalid FAT entry: 0x%08x\n", entry
);
161 switch (mydata
->fatsize
) {
163 bufnum
= entry
/ FAT32BUFSIZE
;
164 offset
= entry
- bufnum
* FAT32BUFSIZE
;
167 bufnum
= entry
/ FAT16BUFSIZE
;
168 offset
= entry
- bufnum
* FAT16BUFSIZE
;
171 bufnum
= entry
/ FAT12BUFSIZE
;
172 offset
= entry
- bufnum
* FAT12BUFSIZE
;
176 /* Unsupported FAT size */
180 debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
181 mydata
->fatsize
, entry
, entry
, offset
, offset
);
183 /* Read a new block of FAT entries into the cache. */
184 if (bufnum
!= mydata
->fatbufnum
) {
185 int getsize
= FATBUFBLOCKS
;
186 __u8
*bufptr
= mydata
->fatbuf
;
187 __u32 fatlength
= mydata
->fatlength
;
188 __u32 startblock
= bufnum
* FATBUFBLOCKS
;
190 if (getsize
> fatlength
)
193 startblock
+= mydata
->fat_sect
; /* Offset from start of disk */
195 /* Write back the fatbuf to the disk */
196 if (flush_dirty_fat_buffer(mydata
) < 0)
199 if (disk_read(startblock
, getsize
, bufptr
) < 0) {
200 debug("Error reading FAT blocks\n");
203 mydata
->fatbufnum
= bufnum
;
206 /* Get the actual entry from the table */
207 switch (mydata
->fatsize
) {
209 ret
= FAT2CPU32(((__u32
*) mydata
->fatbuf
)[offset
]);
212 ret
= FAT2CPU16(((__u16
*) mydata
->fatbuf
)[offset
]);
215 off16
= (offset
* 3) / 4;
217 switch (offset
& 0x3) {
219 ret
= FAT2CPU16(((__u16
*) mydata
->fatbuf
)[off16
]);
223 val1
= FAT2CPU16(((__u16
*)mydata
->fatbuf
)[off16
]);
225 val2
= FAT2CPU16(((__u16
*)mydata
->fatbuf
)[off16
+ 1]);
227 ret
= (val2
<< 4) | (val1
>> 12);
230 val1
= FAT2CPU16(((__u16
*)mydata
->fatbuf
)[off16
]);
232 val2
= FAT2CPU16(((__u16
*)mydata
->fatbuf
)[off16
+ 1]);
234 ret
= (val2
<< 8) | (val1
>> 8);
237 ret
= FAT2CPU16(((__u16
*)mydata
->fatbuf
)[off16
]);
238 ret
= (ret
& 0xfff0) >> 4;
245 debug("FAT%d: ret: %08x, entry: %08x, offset: %04x\n",
246 mydata
->fatsize
, ret
, entry
, offset
);
252 * Set the file name information from 'name' into 'slotptr',
254 static int str2slot(dir_slot
*slotptr
, const char *name
, int *idx
)
258 for (j
= 0; j
<= 8; j
+= 2) {
259 if (name
[*idx
] == 0x00) {
260 slotptr
->name0_4
[j
] = 0;
261 slotptr
->name0_4
[j
+ 1] = 0;
265 slotptr
->name0_4
[j
] = name
[*idx
];
269 for (j
= 0; j
<= 10; j
+= 2) {
270 if (name
[*idx
] == 0x00) {
271 slotptr
->name5_10
[j
] = 0;
272 slotptr
->name5_10
[j
+ 1] = 0;
276 slotptr
->name5_10
[j
] = name
[*idx
];
280 for (j
= 0; j
<= 2; j
+= 2) {
281 if (name
[*idx
] == 0x00) {
282 slotptr
->name11_12
[j
] = 0;
283 slotptr
->name11_12
[j
+ 1] = 0;
287 slotptr
->name11_12
[j
] = name
[*idx
];
292 if (name
[*idx
] == 0x00)
296 /* Not used characters are filled with 0xff 0xff */
298 for (; end_idx
< 5; end_idx
++) {
299 slotptr
->name0_4
[end_idx
* 2] = 0xff;
300 slotptr
->name0_4
[end_idx
* 2 + 1] = 0xff;
305 for (; end_idx
< 6; end_idx
++) {
306 slotptr
->name5_10
[end_idx
* 2] = 0xff;
307 slotptr
->name5_10
[end_idx
* 2 + 1] = 0xff;
312 for (; end_idx
< 2; end_idx
++) {
313 slotptr
->name11_12
[end_idx
* 2] = 0xff;
314 slotptr
->name11_12
[end_idx
* 2 + 1] = 0xff;
320 static int is_next_clust(fsdata
*mydata
, dir_entry
*dentptr
);
321 static void flush_dir_table(fsdata
*mydata
, dir_entry
**dentptr
);
324 * Fill dir_slot entries with appropriate name, id, and attr
325 * The real directory entry is returned by 'dentptr'
328 fill_dir_slot(fsdata
*mydata
, dir_entry
**dentptr
, const char *l_name
)
330 __u8 temp_dir_slot_buffer
[MAX_LFN_SLOT
* sizeof(dir_slot
)];
331 dir_slot
*slotptr
= (dir_slot
*)temp_dir_slot_buffer
;
332 __u8 counter
= 0, checksum
;
335 /* Get short file name checksum value */
336 checksum
= mkcksum((*dentptr
)->name
, (*dentptr
)->ext
);
339 memset(slotptr
, 0x00, sizeof(dir_slot
));
340 ret
= str2slot(slotptr
, l_name
, &idx
);
341 slotptr
->id
= ++counter
;
342 slotptr
->attr
= ATTR_VFAT
;
343 slotptr
->alias_checksum
= checksum
;
348 slotptr
->id
|= LAST_LONG_ENTRY_MASK
;
350 while (counter
>= 1) {
351 if (is_next_clust(mydata
, *dentptr
)) {
352 /* A new cluster is allocated for directory table */
353 flush_dir_table(mydata
, dentptr
);
355 memcpy(*dentptr
, slotptr
, sizeof(dir_slot
));
361 if (is_next_clust(mydata
, *dentptr
)) {
362 /* A new cluster is allocated for directory table */
363 flush_dir_table(mydata
, dentptr
);
367 static __u32 dir_curclust
;
370 * Extract the full long filename starting at 'retdent' (which is really
371 * a slot) into 'l_name'. If successful also copy the real directory entry
373 * If additional adjacent cluster for directory entries is read into memory,
374 * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
375 * the location of the real directory entry is returned by 'retdent'
376 * Return 0 on success, -1 otherwise.
379 get_long_file_name(fsdata
*mydata
, int curclust
, __u8
*cluster
,
380 dir_entry
**retdent
, char *l_name
)
383 dir_slot
*slotptr
= (dir_slot
*)(*retdent
);
384 dir_slot
*slotptr2
= NULL
;
385 __u8
*buflimit
= cluster
+ mydata
->sect_size
* ((curclust
== 0) ?
388 __u8 counter
= (slotptr
->id
& ~LAST_LONG_ENTRY_MASK
) & 0xff;
389 int idx
= 0, cur_position
= 0;
391 if (counter
> VFAT_MAXSEQ
) {
392 debug("Error: VFAT name is too long\n");
396 while ((__u8
*)slotptr
< buflimit
) {
399 if (((slotptr
->id
& ~LAST_LONG_ENTRY_MASK
) & 0xff) != counter
)
405 if ((__u8
*)slotptr
>= buflimit
) {
408 curclust
= get_fatent_value(mydata
, dir_curclust
);
409 if (CHECK_CLUST(curclust
, mydata
->fatsize
)) {
410 debug("curclust: 0x%x\n", curclust
);
411 printf("Invalid FAT entry\n");
415 dir_curclust
= curclust
;
417 if (get_cluster(mydata
, curclust
, get_contents_vfatname_block
,
418 mydata
->clust_size
* mydata
->sect_size
) != 0) {
419 debug("Error: reading directory block\n");
423 slotptr2
= (dir_slot
*)get_contents_vfatname_block
;
424 while (counter
> 0) {
425 if (((slotptr2
->id
& ~LAST_LONG_ENTRY_MASK
)
432 /* Save the real directory entry */
433 realdent
= (dir_entry
*)slotptr2
;
434 while ((__u8
*)slotptr2
> get_contents_vfatname_block
) {
436 slot2str(slotptr2
, l_name
, &idx
);
439 /* Save the real directory entry */
440 realdent
= (dir_entry
*)slotptr
;
445 if (slot2str(slotptr
, l_name
, &idx
))
447 } while (!(slotptr
->id
& LAST_LONG_ENTRY_MASK
));
450 if (*l_name
== DELETED_FLAG
)
452 else if (*l_name
== aRING
)
453 *l_name
= DELETED_FLAG
;
456 /* Return the real directory entry */
460 memcpy(get_dentfromdir_block
, get_contents_vfatname_block
,
461 mydata
->clust_size
* mydata
->sect_size
);
462 cur_position
= (__u8
*)realdent
- get_contents_vfatname_block
;
463 *retdent
= (dir_entry
*) &get_dentfromdir_block
[cur_position
];
470 * Set the entry at index 'entry' in a FAT (12/16/32) table.
472 static int set_fatent_value(fsdata
*mydata
, __u32 entry
, __u32 entry_value
)
474 __u32 bufnum
, offset
, off16
;
477 switch (mydata
->fatsize
) {
479 bufnum
= entry
/ FAT32BUFSIZE
;
480 offset
= entry
- bufnum
* FAT32BUFSIZE
;
483 bufnum
= entry
/ FAT16BUFSIZE
;
484 offset
= entry
- bufnum
* FAT16BUFSIZE
;
487 bufnum
= entry
/ FAT12BUFSIZE
;
488 offset
= entry
- bufnum
* FAT12BUFSIZE
;
491 /* Unsupported FAT size */
495 /* Read a new block of FAT entries into the cache. */
496 if (bufnum
!= mydata
->fatbufnum
) {
497 int getsize
= FATBUFBLOCKS
;
498 __u8
*bufptr
= mydata
->fatbuf
;
499 __u32 fatlength
= mydata
->fatlength
;
500 __u32 startblock
= bufnum
* FATBUFBLOCKS
;
502 fatlength
*= mydata
->sect_size
;
503 startblock
+= mydata
->fat_sect
;
505 if (getsize
> fatlength
)
508 if (flush_dirty_fat_buffer(mydata
) < 0)
511 if (disk_read(startblock
, getsize
, bufptr
) < 0) {
512 debug("Error reading FAT blocks\n");
515 mydata
->fatbufnum
= bufnum
;
519 mydata
->fat_dirty
= 1;
521 /* Set the actual entry */
522 switch (mydata
->fatsize
) {
524 ((__u32
*) mydata
->fatbuf
)[offset
] = cpu_to_le32(entry_value
);
527 ((__u16
*) mydata
->fatbuf
)[offset
] = cpu_to_le16(entry_value
);
530 off16
= (offset
* 3) / 4;
532 switch (offset
& 0x3) {
534 val1
= cpu_to_le16(entry_value
) & 0xfff;
535 ((__u16
*)mydata
->fatbuf
)[off16
] &= ~0xfff;
536 ((__u16
*)mydata
->fatbuf
)[off16
] |= val1
;
539 val1
= cpu_to_le16(entry_value
) & 0xf;
540 val2
= (cpu_to_le16(entry_value
) >> 4) & 0xff;
542 ((__u16
*)mydata
->fatbuf
)[off16
] &= ~0xf000;
543 ((__u16
*)mydata
->fatbuf
)[off16
] |= (val1
<< 12);
545 ((__u16
*)mydata
->fatbuf
)[off16
+ 1] &= ~0xff;
546 ((__u16
*)mydata
->fatbuf
)[off16
+ 1] |= val2
;
549 val1
= cpu_to_le16(entry_value
) & 0xff;
550 val2
= (cpu_to_le16(entry_value
) >> 8) & 0xf;
552 ((__u16
*)mydata
->fatbuf
)[off16
] &= ~0xff00;
553 ((__u16
*)mydata
->fatbuf
)[off16
] |= (val1
<< 8);
555 ((__u16
*)mydata
->fatbuf
)[off16
+ 1] &= ~0xf;
556 ((__u16
*)mydata
->fatbuf
)[off16
+ 1] |= val2
;
559 val1
= cpu_to_le16(entry_value
) & 0xfff;
560 ((__u16
*)mydata
->fatbuf
)[off16
] &= ~0xfff0;
561 ((__u16
*)mydata
->fatbuf
)[off16
] |= (val1
<< 4);
576 * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
577 * and link it to 'entry'. EOC marker is not set on returned entry.
579 static __u32
determine_fatent(fsdata
*mydata
, __u32 entry
)
581 __u32 next_fat
, next_entry
= entry
+ 1;
584 next_fat
= get_fatent_value(mydata
, next_entry
);
586 /* found free entry, link to entry */
587 set_fatent_value(mydata
, entry
, next_entry
);
592 debug("FAT%d: entry: %08x, entry_value: %04x\n",
593 mydata
->fatsize
, entry
, next_entry
);
599 * Write at most 'size' bytes from 'buffer' into the specified cluster.
600 * Return 0 on success, -1 otherwise.
603 set_cluster(fsdata
*mydata
, __u32 clustnum
, __u8
*buffer
,
611 startsect
= mydata
->data_begin
+
612 clustnum
* mydata
->clust_size
;
614 startsect
= mydata
->rootdir_sect
;
616 debug("clustnum: %d, startsect: %d\n", clustnum
, startsect
);
618 if ((unsigned long)buffer
& (ARCH_DMA_MINALIGN
- 1)) {
619 ALLOC_CACHE_ALIGN_BUFFER(__u8
, tmpbuf
, mydata
->sect_size
);
621 printf("FAT: Misaligned buffer address (%p)\n", buffer
);
623 while (size
>= mydata
->sect_size
) {
624 memcpy(tmpbuf
, buffer
, mydata
->sect_size
);
625 ret
= disk_write(startsect
++, 1, tmpbuf
);
627 debug("Error writing data (got %d)\n", ret
);
631 buffer
+= mydata
->sect_size
;
632 size
-= mydata
->sect_size
;
634 } else if (size
>= mydata
->sect_size
) {
635 idx
= size
/ mydata
->sect_size
;
636 ret
= disk_write(startsect
, idx
, buffer
);
638 debug("Error writing data (got %d)\n", ret
);
643 idx
*= mydata
->sect_size
;
649 ALLOC_CACHE_ALIGN_BUFFER(__u8
, tmpbuf
, mydata
->sect_size
);
651 memcpy(tmpbuf
, buffer
, size
);
652 ret
= disk_write(startsect
, 1, tmpbuf
);
654 debug("Error writing data (got %d)\n", ret
);
663 * Find the first empty cluster
665 static int find_empty_cluster(fsdata
*mydata
)
667 __u32 fat_val
, entry
= 3;
670 fat_val
= get_fatent_value(mydata
, entry
);
680 * Write directory entries in 'get_dentfromdir_block' to block device
682 static void flush_dir_table(fsdata
*mydata
, dir_entry
**dentptr
)
684 int dir_newclust
= 0;
686 if (set_cluster(mydata
, dir_curclust
,
687 get_dentfromdir_block
,
688 mydata
->clust_size
* mydata
->sect_size
) != 0) {
689 printf("error: wrinting directory entry\n");
692 dir_newclust
= find_empty_cluster(mydata
);
693 set_fatent_value(mydata
, dir_curclust
, dir_newclust
);
694 if (mydata
->fatsize
== 32)
695 set_fatent_value(mydata
, dir_newclust
, 0xffffff8);
696 else if (mydata
->fatsize
== 16)
697 set_fatent_value(mydata
, dir_newclust
, 0xfff8);
698 else if (mydata
->fatsize
== 12)
699 set_fatent_value(mydata
, dir_newclust
, 0xff8);
701 dir_curclust
= dir_newclust
;
703 if (flush_dirty_fat_buffer(mydata
) < 0)
706 memset(get_dentfromdir_block
, 0x00,
707 mydata
->clust_size
* mydata
->sect_size
);
709 *dentptr
= (dir_entry
*) get_dentfromdir_block
;
713 * Set empty cluster from 'entry' to the end of a file
715 static int clear_fatent(fsdata
*mydata
, __u32 entry
)
719 while (!CHECK_CLUST(entry
, mydata
->fatsize
)) {
720 fat_val
= get_fatent_value(mydata
, entry
);
722 set_fatent_value(mydata
, entry
, 0);
729 /* Flush fat buffer */
730 if (flush_dirty_fat_buffer(mydata
) < 0)
737 * Write at most 'maxsize' bytes from 'buffer' into
738 * the file associated with 'dentptr'
739 * Update the number of bytes written in *gotsize and return 0
740 * or return -1 on fatal errors.
743 set_contents(fsdata
*mydata
, dir_entry
*dentptr
, __u8
*buffer
,
744 loff_t maxsize
, loff_t
*gotsize
)
746 loff_t filesize
= FAT2CPU32(dentptr
->size
);
747 unsigned int bytesperclust
= mydata
->clust_size
* mydata
->sect_size
;
748 __u32 curclust
= START(dentptr
);
749 __u32 endclust
= 0, newclust
= 0;
753 debug("Filesize: %llu bytes\n", filesize
);
755 if (maxsize
> 0 && filesize
> maxsize
)
758 debug("%llu bytes\n", filesize
);
762 debug("error: nonempty clusterless file!\n");
768 actsize
= bytesperclust
;
771 /* search for consecutive clusters */
772 while (actsize
< filesize
) {
773 newclust
= determine_fatent(mydata
, endclust
);
775 if ((newclust
- 1) != endclust
)
778 if (CHECK_CLUST(newclust
, mydata
->fatsize
)) {
779 debug("newclust: 0x%x\n", newclust
);
780 debug("Invalid FAT entry\n");
784 actsize
+= bytesperclust
;
787 /* set remaining bytes */
789 if (set_cluster(mydata
, curclust
, buffer
, (int)actsize
) != 0) {
790 debug("error: writing cluster\n");
795 /* Mark end of file in FAT */
796 if (mydata
->fatsize
== 12)
798 else if (mydata
->fatsize
== 16)
800 else if (mydata
->fatsize
== 32)
801 newclust
= 0xfffffff;
802 set_fatent_value(mydata
, endclust
, newclust
);
806 if (set_cluster(mydata
, curclust
, buffer
, (int)actsize
) != 0) {
807 debug("error: writing cluster\n");
814 if (CHECK_CLUST(newclust
, mydata
->fatsize
)) {
815 debug("newclust: 0x%x\n", newclust
);
816 debug("Invalid FAT entry\n");
819 actsize
= bytesperclust
;
820 curclust
= endclust
= newclust
;
825 * Set start cluster in directory entry
827 static void set_start_cluster(const fsdata
*mydata
, dir_entry
*dentptr
,
830 if (mydata
->fatsize
== 32)
832 cpu_to_le16((start_cluster
& 0xffff0000) >> 16);
833 dentptr
->start
= cpu_to_le16(start_cluster
& 0xffff);
839 static void fill_dentry(fsdata
*mydata
, dir_entry
*dentptr
,
840 const char *filename
, __u32 start_cluster
, __u32 size
, __u8 attr
)
842 set_start_cluster(mydata
, dentptr
, start_cluster
);
843 dentptr
->size
= cpu_to_le32(size
);
845 dentptr
->attr
= attr
;
847 set_name(dentptr
, filename
);
851 * Check whether adding a file makes the file system to
852 * exceed the size of the block device
853 * Return -1 when overflow occurs, otherwise return 0
855 static int check_overflow(fsdata
*mydata
, __u32 clustnum
, loff_t size
)
857 __u32 startsect
, sect_num
, offset
;
860 startsect
= mydata
->data_begin
+
861 clustnum
* mydata
->clust_size
;
863 startsect
= mydata
->rootdir_sect
;
866 sect_num
= div_u64_rem(size
, mydata
->sect_size
, &offset
);
871 if (startsect
+ sect_num
> cur_part_info
.start
+ total_sector
)
877 * Check if adding several entries exceed one cluster boundary
879 static int is_next_clust(fsdata
*mydata
, dir_entry
*dentptr
)
883 cur_position
= (__u8
*)dentptr
- get_dentfromdir_block
;
885 if (cur_position
>= mydata
->clust_size
* mydata
->sect_size
)
891 static dir_entry
*empty_dentptr
;
893 * Find a directory entry based on filename or start cluster number
894 * If the directory entry is not found,
895 * the new position for writing a directory entry will be returned
897 static dir_entry
*find_directory_entry(fsdata
*mydata
, int startsect
,
898 char *filename
, dir_entry
*retdent
, __u32 start
)
900 __u32 curclust
= (startsect
- mydata
->data_begin
) / mydata
->clust_size
;
902 debug("get_dentfromdir: %s\n", filename
);
909 if (get_cluster(mydata
, curclust
, get_dentfromdir_block
,
910 mydata
->clust_size
* mydata
->sect_size
) != 0) {
911 printf("Error: reading directory block\n");
915 dentptr
= (dir_entry
*)get_dentfromdir_block
;
917 dir_curclust
= curclust
;
919 for (i
= 0; i
< DIRENTSPERCLUST
; i
++) {
920 char s_name
[14], l_name
[VFAT_MAXLEN_BYTES
];
923 if (dentptr
->name
[0] == DELETED_FLAG
) {
925 if (is_next_clust(mydata
, dentptr
))
929 if ((dentptr
->attr
& ATTR_VOLUME
)) {
931 (dentptr
->attr
& ATTR_VFAT
) &&
932 (dentptr
->name
[0] & LAST_LONG_ENTRY_MASK
)) {
933 get_long_file_name(mydata
, curclust
,
934 get_dentfromdir_block
,
936 debug("vfatname: |%s|\n", l_name
);
938 /* Volume label or VFAT entry */
940 if (is_next_clust(mydata
, dentptr
))
945 if (dentptr
->name
[0] == 0) {
946 debug("Dentname == NULL - %d\n", i
);
947 empty_dentptr
= dentptr
;
951 get_name(dentptr
, s_name
);
953 if (strcmp(filename
, s_name
)
954 && strcmp(filename
, l_name
)) {
955 debug("Mismatch: |%s|%s|\n",
958 if (is_next_clust(mydata
, dentptr
))
963 memcpy(retdent
, dentptr
, sizeof(dir_entry
));
965 debug("DentName: %s", s_name
);
966 debug(", start: 0x%x", START(dentptr
));
967 debug(", size: 0x%x %s\n",
968 FAT2CPU32(dentptr
->size
),
969 (dentptr
->attr
& ATTR_DIR
) ?
976 * In FAT16/12, the root dir is locate before data area, shows
978 * -------------------------------------------------------------
979 * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
980 * -------------------------------------------------------------
982 * As a result if curclust is in Root dir, it is a negative
986 if (mydata
->fatsize
!= 32 && (int)curclust
<= 1) {
987 /* Current clust is in root dir, set to next clust */
989 if ((int)curclust
<= 1)
990 continue; /* continue to find */
992 /* Reach the end of root dir */
993 empty_dentptr
= dentptr
;
997 curclust
= get_fatent_value(mydata
, dir_curclust
);
998 if (IS_LAST_CLUST(curclust
, mydata
->fatsize
)) {
999 empty_dentptr
= dentptr
;
1002 if (CHECK_CLUST(curclust
, mydata
->fatsize
)) {
1003 debug("curclust: 0x%x\n", curclust
);
1004 debug("Invalid FAT entry\n");
1012 static int do_fat_write(const char *filename
, void *buffer
, loff_t size
,
1015 dir_entry
*dentptr
, *retdent
;
1017 __u32 start_cluster
;
1019 volume_info volinfo
;
1021 fsdata
*mydata
= &datablock
;
1023 int ret
= -1, name_len
;
1024 char l_filename
[VFAT_MAXLEN_BYTES
];
1029 if (read_bootsectandvi(&bs
, &volinfo
, &mydata
->fatsize
)) {
1030 debug("error: reading boot sector\n");
1034 total_sector
= bs
.total_sect
;
1035 if (total_sector
== 0)
1036 total_sector
= (int)cur_part_info
.size
; /* cast of lbaint_t */
1038 if (mydata
->fatsize
== 32)
1039 mydata
->fatlength
= bs
.fat32_length
;
1041 mydata
->fatlength
= bs
.fat_length
;
1043 mydata
->fat_sect
= bs
.reserved
;
1045 cursect
= mydata
->rootdir_sect
1046 = mydata
->fat_sect
+ mydata
->fatlength
* bs
.fats
;
1047 num_of_fats
= bs
.fats
;
1049 mydata
->sect_size
= (bs
.sector_size
[1] << 8) + bs
.sector_size
[0];
1050 mydata
->clust_size
= bs
.cluster_size
;
1052 if (mydata
->fatsize
== 32) {
1053 mydata
->data_begin
= mydata
->rootdir_sect
-
1054 (mydata
->clust_size
* 2);
1058 rootdir_size
= ((bs
.dir_entries
[1] * (int)256 +
1059 bs
.dir_entries
[0]) *
1060 sizeof(dir_entry
)) /
1062 mydata
->data_begin
= mydata
->rootdir_sect
+
1064 (mydata
->clust_size
* 2);
1067 mydata
->fatbufnum
= -1;
1068 mydata
->fat_dirty
= 0;
1069 mydata
->fatbuf
= memalign(ARCH_DMA_MINALIGN
, FATBUFSIZE
);
1070 if (mydata
->fatbuf
== NULL
) {
1071 debug("Error: allocating memory\n");
1075 if (disk_read(cursect
,
1076 (mydata
->fatsize
== 32) ?
1077 (mydata
->clust_size
) :
1078 PREFETCH_BLOCKS
, do_fat_read_at_block
) < 0) {
1079 debug("Error: reading rootdir block\n");
1082 dentptr
= (dir_entry
*) do_fat_read_at_block
;
1084 name_len
= strlen(filename
);
1085 if (name_len
>= VFAT_MAXLEN_BYTES
)
1086 name_len
= VFAT_MAXLEN_BYTES
- 1;
1088 memcpy(l_filename
, filename
, name_len
);
1089 l_filename
[name_len
] = 0; /* terminate the string */
1090 downcase(l_filename
);
1092 startsect
= mydata
->rootdir_sect
;
1093 retdent
= find_directory_entry(mydata
, startsect
,
1094 l_filename
, dentptr
, 0);
1096 /* Update file size and start_cluster in a directory entry */
1097 retdent
->size
= cpu_to_le32(size
);
1098 start_cluster
= START(retdent
);
1100 if (start_cluster
) {
1102 ret
= check_overflow(mydata
, start_cluster
,
1105 printf("Error: %llu overflow\n", size
);
1110 ret
= clear_fatent(mydata
, start_cluster
);
1112 printf("Error: clearing FAT entries\n");
1117 set_start_cluster(mydata
, retdent
, 0);
1119 ret
= start_cluster
= find_empty_cluster(mydata
);
1121 printf("Error: finding empty cluster\n");
1125 ret
= check_overflow(mydata
, start_cluster
, size
);
1127 printf("Error: %llu overflow\n", size
);
1131 set_start_cluster(mydata
, retdent
, start_cluster
);
1134 /* Set short name to set alias checksum field in dir_slot */
1135 set_name(empty_dentptr
, filename
);
1136 fill_dir_slot(mydata
, &empty_dentptr
, filename
);
1139 ret
= start_cluster
= find_empty_cluster(mydata
);
1141 printf("Error: finding empty cluster\n");
1145 ret
= check_overflow(mydata
, start_cluster
, size
);
1147 printf("Error: %llu overflow\n", size
);
1154 /* Set attribute as archieve for regular file */
1155 fill_dentry(mydata
, empty_dentptr
, filename
,
1156 start_cluster
, size
, 0x20);
1158 retdent
= empty_dentptr
;
1161 ret
= set_contents(mydata
, retdent
, buffer
, size
, actwrite
);
1163 printf("Error: writing contents\n");
1166 debug("attempt to write 0x%llx bytes\n", *actwrite
);
1168 /* Flush fat buffer */
1169 ret
= flush_dirty_fat_buffer(mydata
);
1171 printf("Error: flush fat buffer\n");
1175 /* Write directory table to device */
1176 ret
= set_cluster(mydata
, dir_curclust
, get_dentfromdir_block
,
1177 mydata
->clust_size
* mydata
->sect_size
);
1179 printf("Error: writing directory entry\n");
1182 free(mydata
->fatbuf
);
1186 int file_fat_write(const char *filename
, void *buffer
, loff_t offset
,
1187 loff_t maxsize
, loff_t
*actwrite
)
1190 printf("Error: non zero offset is currently not supported.\n");
1194 printf("writing %s\n", filename
);
1195 return do_fat_write(filename
, buffer
, maxsize
, actwrite
);